Uncovering the cornerstones of our Universe: Application and Development of Next-Generation Stellar Atmospheres

揭示宇宙的基石：下一代恒星大气的应用和发展

• 批准号: 445674056
• 负责人: Dr. Andreas Sander
• 金额: --
• 依托单位: Astronomisches Rechen-Institut
• 依托单位国家: 德国
• 项目类别: Independent Junior Research Groups
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/445674056?language=en
• 关键词: Uncovering; cornerstones; our; Universe; Application

Massive stars and their interaction with the environment are keystones of modern astrophysics. Their influence ranges from the first stars over the chemical evolution of galaxies up to the progenitors of supernovae and gravitational wave events. Despite their importance, the quantitative impact of massive stars is poorly constrained and current descriptions turn out to be insufficient. This significantly blurs our perception of stellar evolution in the upper mass regime and obscures our interpretation of processes crucially dependent on stellar feedback, such as stellar population synthesis or the nature of massive black holes.To constrain and predict the properties of massive stars, such as their spectra, winds, and feedback, proper modelling of their expanding atmospheres is essential. This requires a complex numerical treatment in a non-equilibrium environment, for which the hydrodynamic structure is traditionally approximated by means of an analytical description. However, this description has proven to be insufficient. Especially for evolved stars, significant discrepancies arise between the parameters predicted by stellar evolution and those obtained via model atmospheres. The consequences are fundamental uncertainties in the properties and evolution of massive stars, which can reach orders of magnitude when extrapolating current descriptions to earlier cosmic times. The interpretation of gravitational wave events and the oncoming era of high-redshift astrophysics more than ever rely on a robust knowledge of massive stars and their feedback. Thus, a dangerous gap emerges between our observational capabilities and our theoretical understanding.My Emmy Noether research group aims at closing this gap by focussing on one of the key tools in the field of modern astrophysics: The application and development of stellar atmospheres. My efforts over the past years have paved the way for a new generation of stellar atmospheres, capable of overcoming the limitations of classical approaches by coupling the radiative transfer with consistent hydrodynamics. With this technique, it is possible to capture the full physics inherent to hot star winds and predict the feedback consistently from a given set of stellar parameters. My research group will revise our understanding of radiatively-driven winds and obtain a coherent picture of hot star feedback at different regimes and metallicities, ranging even back to the first stars. With analytical and theoretical applications of next-generation atmospheres, we can trace all relevant stages of hot star evolution and investigate the impact on stellar populations. By coupling atmosphere and structure models, we will establish a new level of consistency in stellar evolution. All of these efforts will be complemented by the constant extension and improvement of the model atmosphere code, which will further be made accessible to the whole astrophysical community.

大质量恒星及其与环境的相互作用是现代天体物理学的重点。它们的影响范围从第一颗恒星到星系的化学演化，再到超新星和引力波事件的前身。尽管它们很重要，但大质量恒星的定量影响受到很大的限制，目前的描述是不够的。这极大地模糊了我们对高质量恒星演化的认识，也模糊了我们对恒星反馈过程的解释，如恒星的人口合成或大质量黑洞的性质。为了约束和预测大质量恒星的性质，如它们的光谱、风和反馈，对它们膨胀的大气进行适当的建模是必不可少的。这需要在非平衡环境中进行复杂的数值处理，对于非平衡环境，传统上通过解析描述来近似流体动力学结构。然而，这种描述已被证明是不够的。特别是对于演化的恒星，恒星演化预测的参数与通过模型大气获得的参数之间存在显着差异。其后果是大质量恒星的性质和演化存在根本的不确定性，当将当前的描述外推到更早的宇宙时代时，这种不确定性可能达到数量级。对引力波事件的解释和即将到来的高红移天体物理学时代比以往任何时候都更加依赖于对大质量恒星及其反馈的强大知识。因此，我们的观测能力和理论理解之间出现了一个危险的差距。我的Emmy Noether研究小组旨在通过专注于现代天体物理学领域的关键工具之一来缩小这一差距：恒星大气的应用和发展。我在过去几年的努力为新一代恒星大气铺平了道路，能够通过将辐射传递与一致的流体力学相结合来克服经典方法的局限性。有了这项技术，就有可能捕捉到热星星风所固有的全部物理特性，并从给定的一组恒星参数中一致地预测反馈。我的研究小组将修改我们对辐射驱动风的理解，并获得不同制度和金属丰度下热星星反馈的连贯图像，甚至可以追溯到第一颗恒星。通过对下一代大气的分析和理论应用，我们可以追踪热星星演化的所有相关阶段，并研究对恒星种群的影响。通过耦合大气和结构模型，我们将在恒星演化中建立一个新的一致性水平。所有这些努力将得到不断扩大和改进大气模型代码的补充，该代码将进一步向整个天体物理界开放。